← Back to dex
Rare exoplanet 49 EP

GJ 504 b

RA 199.1923° · Dec 9.4250° · exoplanet

Loading sky survey…
🌌 View in 3D star map
Tonight’s visibility

Computing the sky for your location…

Score breakdown

· 5 badges
49 pts · Rare
Rare 50 pts → Epic
  • Directly imaged +16
  • Its star is visible to the naked eye +12
  • Orbits beyond Neptune's distance +12
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 49

1 more point to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Directly imaged · +16
  • Its star is visible to the naked eye · +12
  • Orbits beyond Neptune's distance · +12

Trivia

What it actually is

  • What it is made of. Its density says rock, though lighter than Earth's mix: probably less iron, or a thick shell of water and ice over the top.

Sense of scale

  • In perspective. Inside our stellar backyard: every radio broadcast humanity has ever made has already swept past it.

Find it in the sky

  • How to spot it. At magnitude 5.2 you can see it with your own eyes from a dark site.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • Best time of year. It stands highest in the middle of the night around April — that's when to go looking.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Getting there

  • Aboard Voyager 1. ≈ 1 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 89.3 thousand years even at the Parker Solar Probe's 192 km/s.

Properties

density gcc
3.94
diameter km
154422.7196
discovery facility
Subaru Telescope
discovery method
Imaging
discovery year
2013
dist ly
57.1748
eq temp k
510
host star teff
6234
insolation
0.0011
mag
5.188
mass earth
1271.3
name
GJ 504 b
radius earth
12.1057
semi major au
43.5
spect
G0 V
sys num planets
1
sys num stars
1

About GJ 504 b

GJ 504 b is a rare exoplanet. It lies about 57.2 light-years from Earth, shines at apparent magnitude 5.19, has spectral type G0 V and has an equilibrium temperature near 510 K.

Its density says rock, though lighter than Earth's mix: probably less iron, or a thick shell of water and ice over the top.

How to see it

At apparent magnitude 5.19, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, GJ 504 b is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. The visibility panel above works out tonight's viewing window for your saved location.

Why GJ 504 b is a rare exoplanet

GJ 504 b scores 49 points on Spacedle's rarity scale, which places it in the rare tier. Another 1 point would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Gas giant, Directly imaged, Its star is visible to the naked eye and Orbits beyond Neptune's distance — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.